JP3029326U - Multi-stage airbag inflator - Google Patents

Abstract

[PROBLEMS] To provide a multistage airbag inflator capable of satisfactorily exhibiting optimum functions over a wide range of collision situations. An inflator 20 includes an inner wall structure 34, and
The housing 22 is divided into two compartments 30 and 32. Each of the chambers 30 and 32 accommodates a large number of gas generating materials 40. The small first chamber 30 and the large second chamber 32 house squibs 44 and 52, respectively. The inner wall structure 34 includes a support member 60 having a central hole 60a. Rupture plate 62
Is broken by the gas pressure at the time of ignition of the gas generating material 40 in the first chamber 30, but is supported against the gas pressure at the time of ignition of the gas generating material 40 in the second chamber 32. The hot gas from the first chamber 30 flows through the center hole 60a and ignites the gas generating material 40 in the second chamber 32. The heat insulating material layer 64 is provided in the second chamber 3
The heat generated by the ignition of the gas generating material 40 of No. 2 is generated in the first chamber 30.
It is possible to prevent the gas generating material 40 from being ignited.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a multi-stage airbag inflator capable of adjusting the degree of gas flow according to the severity of collision (that is, collision strength). In particular, the present invention relates to a multi-stage airbag inflator having one housing divided into at least two independent chambers by an inner wall, and each chamber containing a gas generating charge and its ignition device. In this multi-stage airbag inflator, the inner wall is provided with a fragile portion that ruptures in response to gas pressure in one chamber but is supported against rupture by gas pressure in the other chamber. Therefore, in a collision with a certain intensity, only one chamber will operate, and in a collision with another intensity, both chambers will operate.

[0002]

[Prior art]

 U.S. Pat. No. 5,330,226 discloses a method and apparatus for detecting an occupant who has deviated (i.e., sedated) from a predetermined position to control the operation of a vehicle occupant restraint system. The device comprises a remote vent valve that allows the gas generated from one or both of the two inflation devices provided to inflate one airbag restraint.

US Pat. No. 5,074,583 discloses an automotive airbag system with a housing containing a plurality of independently controlled inflator devices. Each inflator includes a release valve that opens to inflate the airbag when a gas pressure above a predetermined value is generated. US Pat. No. 5,232,243 discloses an occupant sensing device used in an occupant restraint system. Preferably, the occupant sensing device monitors the occupant seat in the vehicle to detect the presence, position and weight of objects on the seat. The execution of the control algorithm controls the inflation of the airbag in response to the detected value.

US Pat. No. 4,243,248 discloses an airbag system including a driver airbag and a front passenger occupant airbag. In this airbag system, the occupant side airbag can be inflated in two stages in response to the main force signal generated from the sensor system when the deceleration reaches the first threshold value and the second threshold value. U.S. Pat. No. 3,767,228 discloses a controller for controlling the inflation actuation of an airbag. This control device controls in response to the ambient temperature inside the vehicle in which it is installed.

US Pat. No. 5,074,583 discloses an automobile airbag system including a seating condition sensor for detecting a seating position, a backrest angle, a physique and a seating condition of an occupant. The airbag is actuated in accordance with the occupant's seating condition so that the occupant is contacted best when inflated. U.S. Pat. No. 4,984,651 discloses a vehicle occupant restraint system including a switch member for detecting a working position of a safety belt. The airbag and belt tensioner are activated depending on the position of action of the safety belt.

US Pat. No. 4,998,751 discloses a two-stage automotive airbag inflator with an ignition material that delays a second ignition stage. The expander has two compartments, and the ignition material in the second compartment burns more slowly than the ignition material in the first compartment. US Pat. No. 5,071,160 discloses a sensor for detecting the position of an occupant. This sensor allows the airbag to be deployed and deployed to provide optimal protection for the occupant.

US Pat. No. 3,672,699 discloses an automatic restraint system that controls the inflation of an airbag in response to the presence or absence of an occupant. If the occupant is absent, the airbag will not be inflated. U.S. Pat. No. 4,620,721 discloses an airbag system which is also responsive to whether or not the driver is using a seat belt. The difference from the above is that the threshold differs depending on the driver's belt usage.

US Pat. No. 3,767,002 discloses a seat occupancy sensitive airbag actuation and monitoring circuit. This circuit detects the presence of an occupant before firing an igniter (ie, a skib) that controls the inflation of the airbag. U.S. Pat. No. 3,966,224 discloses an airbag system having multiple stages of inflation rate using an air augmented inflator. The inflator is activated in various ways when impacts of different predetermined levels of strength occur to achieve various inflation rates.

[0009]

[Problems to be solved by the device]

 The purpose of the present invention is to provide a new and improved multi-stage airbag inflator that performs optimally in a wider range of crash situations than is possible with conventional airbag inflator systems. To provide a system. Another object of the present invention is to provide a new and improved multi-stage airbag inflator.

Yet another object of the present invention is to provide a new and improved multi-stage airbag inflator which has selectively controllable performance characteristics and exhibits multi-stage energy absorption capacity. Especially. Still another object of the present invention is to provide a new and improved multi-stage airbag inflation system capable of treating the mass flow rate of the airbag inflation gas and exhibiting a level suppression capability in a timely manner.

[0011]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is provided with a plurality of chambers that are independent of each other, each housing containing a gas generating means and an igniting means, and a plurality of chambers provided in the housing and dividing the housing. And an inner wall means having a fragile portion that ruptures in response to gas pressure generated in one of the plurality of chambers to allow fluid communication between the chambers. A multi-stage air bag inflator is provided.

Further, the present invention is, in the above-mentioned multi-stage airbag inflator, wherein the fragile portion responds to a gas pressure generated in another chamber of the plurality of chambers when the ignition means is activated. Provided is a multi-stage airbag inflator having a sufficient strength to prevent the air bag from bursting. Further, the present invention provides the above-mentioned multistage airbag inflator, wherein the inner wall means includes a supporting means for supporting the fragile portion on at least one surface thereof.

The present invention also provides the above-described multi-stage airbag inflator, wherein the supporting means has at least one hole for allowing gas to flow between the plurality of chambers. Further, the present invention is the above-mentioned multi-stage airbag inflator, wherein the supporting means has a perforated structure having holes for allowing gas to flow between the plurality of chambers, and the fragile portion is separated from the supporting means. A multi-stage airbag inflator having at least one groove formed on the other side of the weakened portion on one side, the groove forming a break line that ruptures the weakened portion in response to gas pressure generated in one chamber. provide.

Further, the present invention is, in the above-mentioned multi-stage airbag inflator, in which the support means is engaged with one surface of the fragile portion and responds to a gas pressure generated in the other of the plurality of chambers. Provided is a multi-stage airbag inflator which supports a fragile portion against rupture. Further, the present invention is the above-mentioned multi-stage airbag inflator, wherein one surface of the fragile portion is flat, and the groove forms a thin wall portion, and the fragile portion responds to the gas pressure generated adjacent to the one surface. To provide a multi-stage airbag inflator which promotes rupture of a portion.

Further, the present invention provides that, in the above-described multi-stage airbag inflator, the inner wall means activates the gas generating means of one chamber by the heat generated when the gas generating means of the other chamber is activated. Provided is a multi-stage airbag inflator having a heat insulating means for preventing. Further, the present invention provides the above multi-stage airbag inflator, wherein the inner wall means comprises a structural support having a hole for allowing gas to flow between the plurality of chambers, and the thermal insulation means is at least one of the supports. There is provided a multi-stage airbag inflator supported adjacent to the surface of the vehicle.

Further, the present invention provides the above-mentioned multi-stage airbag inflator, in which the fragile portion of the inner wall means is supported on the other surface of the support on the side remote from the heat insulating means. provide. Thus, the multi-stage airbag inflator according to the present invention may include a housing having a plurality of gas outlets that open directly to the inflated airbag. The housing includes at least two compartments, each of which can contain a predetermined amount of gas generating material and a gas generating material ignition device for rapidly inflating an airbag. The housing is provided with an inner wall structure that defines a compartment. The inner wall structure includes a weakened portion that ruptures in response to gas pressure generated in one chamber but is supported against gas ruptured in another chamber. When an ignition device arranged in one or both chambers is activated, a desired amount of gas generated from one or both chambers inflates the airbag. The time delay between ignitions of multiple igniters is set according to the identified collision type.

[0017]

[Embodiment of device]

 1 and 2 show a multi-stage airbag inflator 20 according to an embodiment of the present invention. The inflator 20 is used in an air bag system 10 that provides variable timing and variable inflation levels. In particular, the inflator 20 is capable of deploying the airbag in a multi-pulse manner to suit various sensed conditions and crash intensities.

The expansion device 20 includes a substantially cylindrical metal housing 22. The housing 22 includes a hollow cylindrical side wall 24, a circular end wall 26 integrally formed with the side wall 24 to close one end thereof, and an annular end plate 28 closing the other end of the side wall 24. The annular end plate 28 is supported at a predetermined position by an end locking flange 24a integrally formed at the other open end of the side wall 24 and extending inward in the radial direction. An annular seal ring 29 is interposed between the annular inner surface of the locking flange 24a and the peripheral edge portion of the outer surface of the annular end plate 28.

The interior of the housing 22 is divided into at least two independent compartments 30, 32 by an inner wall structure 34. Each of the chambers 30 and 32 has a large number of gas discharge ports 30a and 32a. Each outlet 30a, 32a directs gas radially outward, as indicated by arrows A, B, respectively, to rapidly inflate an associated air bag (not shown) in communication therewith. A foil seal plate 36 is attached to the inner surface of the cylindrical side wall 24 of each chamber 30 and 32 with an adhesive agent, and the discharge port 30a and 32a of the housing 22 protects the housing 22 from intrusion of unwanted contaminants from the outside of the housing. Seal the inside. When the internal gas pressure is generated in the chambers 30 and 32 by starting the inflator, the sealing plate 36 is easily ruptured to open the discharge ports 30a and 32a and rapidly discharge the gas to inflate the airbag.

Each chamber 30, 32 contains a charge of solid gas generating material 40 in the form of a number of pellets or wafers made of sodium azide or other material. The gas generating material (pellet) 40 rapidly generates a relatively large amount of non-toxic gas for inflating the airbag when ignited. Each chamber 30, 32 further comprises a tubular gas filter 42 formed from one or more layers of metallic shielding, ceramic porous or other type of filtration media. The gas filter 42 removes high temperature slag and particulate matter from the gas generated from the large number of gas generating materials 40 before the gas is discharged from the discharge ports 30a and 32a.

As shown, the first chamber 30 is relatively small and the second chamber 32 is relatively large. However, this ratio can be varied within the scope of the invention. For example, as shown in FIG. 1, the first chamber 30 can be smaller than the second chamber 32. Further, the first chamber 30 and the second chamber 32 may have the same size, or the first chamber 30 may be larger than the second chamber 32. The first chamber 30, which is an independent combustion chamber, includes an electrically activated ignition tube (or squib) 44 that is closely mounted in the center hole 28a of the end plate 28. The squib 44 is held in place by an annular member 27 that surrounds it and is attached to the end plate 28. The squib 44 comprises a plurality of outwardly projecting electrical terminals 44a, which are connected via terminal sockets 46 to a plurality of electrical wires 48 which carry electrical ignition signals from the sensing and control system described below. . The squib 44 may also include a container 50 of ignition enhancing material such as BKNO ₃ . When the squib 44 is electrically activated by the pulse signal, the ignition action is enhanced, and a large number of the gas generating materials 40 are rapidly ignited to generate a predetermined amount of inflation gas to rapidly inflate the airbag.

The second chamber 32, which is an independent combustion chamber, includes another squib 52. The squib 52 comprises a plurality of external terminals 52a connected to the sensing and control system via a connector 54 and a plurality of electrical wires 56. The squib 52 may also include a container 58 of ignition enhancing material such as BKNO ₃ . The squib 52 is tightly mounted in the central hole 26a of the integral end wall 26 of the housing 22 and is held in place by an annular member 31 surrounding it and attached to the end wall 26.

The inner wall structure 34, which is a partition wall that divides the inside of the housing 22 into a first chamber 30 and a second chamber 32, includes a strong annular support member 60 made of metal. The outer edge of the support member 60 is snap-fitted or fixed to a shoulder surface 24b formed on the inner surface of the tubular side wall 24 of the housing 22. The support member 60 has a center hole 60a. When the gas generating material 40 in the first chamber 30 is ignited, the center hole 60a enables the gas pressure to be transmitted to the thin circular rupturable plate 62 made of metal and pierce it (FIG. 2).

Since the center hole 60 a of the annular support member 60 has a relatively small diameter, the rupture plate 62 is not broken when the gas generating material 40 in the second chamber 32 is ignited, and the pressure transmission between the rupture plate 62 and the first chamber 30 is prevented. Is not allowed and the pressure in the second chamber 32 is maintained (FIG. 1). Since the back surface of the rupture plate 62 has a relatively large area, the rupture plate 62 is broken by the gas pressure when the gas generating material 40 in the first chamber 30 is ignited. There, the hot gas from the first chamber 30 flows through the central hole 60a and the ruptured rupture plate 62 and ignites the gas generating material 40 in the second chamber 32. The heat insulating material layer 64 does not need to be gas impermeable and has a slight mechanical support function, but is attached to the support member 60 in the first chamber 30 to be connected to the first chamber 30. Thermal insulation is provided between the gas generating material 40 and the second chamber 32, and heat generated by ignition of the gas generating material 40 in the second chamber 32 is prevented from igniting the gas generating material 40 in the first chamber 30. If the first chamber 30 and the second chamber 32 have the same size, or if the first chamber 30 is larger than the second chamber 32, the rupture plate 62 can be arranged in the first chamber 30.

As shown in FIG. 3, a plurality of score lines or grooves 62 a are provided on the right-hand surface of the rupture plate 62 in FIG. 2 so that the gas pressure in the first chamber 30 is changed to the second chamber. The rupture of the rupture plate 62 when it becomes larger than that is promoted. Such a situation occurs when the squib 44 is first activated and the gas generating material 40 in the first chamber 30 generates gas before the ignition of the gas generating material 40 in the second chamber 32. . The high gas pressure in the first chamber 30 passes through or breaks through the heat insulating material layer 64, moves through the central hole 60a of the annular support member 60, reaches the entire back surface of the rupture plate 62, and flexes the rupture plate 62. No (shown in dashed lines in Figure 2), finally break through as shown. The rupture of the rupture plate 62 is facilitated by the weakening groove 62a and because there is no structural support for the rupture plate 62 in the second chamber 32.

The high-temperature combustion products generated from the gas generating material 40 in the first chamber 30 enter the second chamber 32 as shown by an arrow C in FIG. 2 and are disposed adjacent to the inner wall structure 34. The material 40a is ignited. As a result, this action ignites all the gas generating materials 40 in the second chamber 32 to generate the maximum amount of gas. At this time, a time delay occurs between the first ignition of the gas generating material 40 in the first chamber 30 and the next ignition pulse due to the ignition of the gas generating materials 40a, 40 in the second chamber 32.

In order to further promote the rupture of the rupture plate 62, a circular spacer 65 can be installed in the large second chamber 32 apart from the rupture plate 62. The spacer 65 prevents the gas generating material 40 from being pressed directly against the rupture plate 62 and supporting the rupture plate 62 against the rupture action by the gas pressure from the small first chamber 30. The spacer 65 is relatively weak in itself, and is easily pierced by the rupture plate 62 which ruptures due to the gas pressure from the first chamber 30.

When the squib 52 in the second chamber 32 is first activated, the gas pressure generated in the second chamber 32 is such that the rupture plate 62 is sufficiently supported by the support member 60 on the left side of FIG. Therefore, it is not enough to break the rupturable plate 62 and allow the gas to flow into the first chamber 30. Moreover, the heat generated in the combustion process in the second chamber 32 cannot ignite the gas generating material 40 in the first chamber 30 due to the presence of the heat insulating material layer 64.

After the first ignition of the second chamber 32 has begun, the gas generant 40 of the first chamber 30 can be ignited when required by an electrical pulse signal sent to the squib 44. The timing of the ignition signal output to each squib 52, 44 can be selectively controlled by a sensing and control system described below to obtain the desired pulsed inflation characteristics of the airbag. FIG. 4 shows the airbag system 10 in a block diagram representation. The airbag system 10 includes an electric control device 100, a power supply 102, and a plurality of sensors displayed by a multistage sensor block 104 connected to the electric control device 100. Electrical controller 100 is suitably programmed to perform the control functions shown in FIG. A set of power stage / monitor blocks 106, 108 are connected to the electrical control unit 100 and the power supply 102 and to the ignition controller squibs 44, 52 via wires 48, 56, respectively. The power stage / monitor blocks 106, 108 can provide energy to the squibs 44, 52. A monitor function included in the power stage / monitor block 106, 108 monitors the shutdown mode of the power stage and subsequent skibs 44, 52. The multi-stage sensor 104 includes an acceleration sensor, a driver side temperature sensor, an occupant side temperature sensor, a driver side buckle switch, an occupant side buckle switch, a driver side occupant sensor, an occupant side occupant sensor, and a selective occupant side occupant seating. It is advantageous to include a sensor.

For reference, US Pat. No. 5,411,289 (issued May 2, 1995, filing date October 29, 1993) discloses an electric control device, a power supply, and a multi-stage sensor as described above. An automotive airbag system that is coupled to several levels of gas sources is disclosed. FIG. 5 is a flow chart showing the sequential steps performed by the electrical controller 100. Continuous operation is initiated by the electronic controller 100 monitoring the multi-stage sensor 104 (block 400). The electrical controller 100 identifies the occurrence of a collision based on the monitored sensor input signal (decision block 402). If the decision block 402 identifies a collision, the electrical control unit 100 measures the change in vehicle speed (block 404). The electrical controller 100 then identifies the crash intensity or crash type (block 406). The electrical controller 100 then determines whether both squibs 1, 2 (corresponding to squibs 44, 52, respectively) should be fired or fired (decision block 408). If it is determined that both squibs should be fired, the electronic controller 100 fires squib 1 (block 410) and confirms the selected time delay value (block 412). After a selected time delay of, for example, 50 milliseconds or less, electrical controller 100 fires squib 2 (block 414).

On the other hand, if it is determined at decision block 408 that both squibs 1 and 2 do not need to be fired, electrical controller 100 determines which squibs 1 or 2 should be fired (decision block 416). If the squib 2 is qualified as a suitable ignition controller, the electrical controller 100 ignites the qualified squib 2 (block 418). Also, if the squib 1 is qualified as a suitable ignition controller, the electrical control device 100 ignites the qualified squib 1 (block 420).

Although the present invention has been described above with reference to its embodiments, the present invention is not limited thereto, and various modifications and changes can be made without departing from the description of the scope of claims for utility model registration. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a multi-stage airbag inflator according to an embodiment of the present invention in an operating state in which only a gas generating material in one compartment is ignited to generate a minimum gas flow for inflating an airbag. is there.

FIG. 2 is a sectional view corresponding to FIG. 1, showing another operating state in which the gas generating material in both compartments is ignited to generate a maximum gas flow.

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG.

FIG. 4 is a block diagram of an airbag system used with the airbag inflator of FIG.

5 is a flow chart showing successive steps performed by an electrical controller in the airbag system of FIG.

[Explanation of symbols]

 20 ... Multi-stage airbag inflator 22 ... Housing 30 ... First chamber 32 ... Second chamber 34 ... Inner wall structure 40 ... Gas generating material 44, 52 ... Squib 60 ... Support member 62 ... Bursting plate 65 ... Spacer

Claims (10)

[Scope of utility model registration request] 1. A housing having a plurality of chambers independent of each other, each housing containing a gas generating means and an ignition means, and an inner wall means provided in the housing and dividing the housing to form the plurality of chambers. An inner wall means having a weakened portion that ruptures in response to a gas pressure generated in one of the plurality of chambers to allow fluid communication between the chambers. A multi-stage airbag inflator. 2. The weakened portion is sufficient to prevent rupture in response to gas pressure generated in the other chamber of the plurality of chambers when the ignition means is activated. The multi-stage airbag inflator according to claim 1, which has strength. 3. The multi-stage airbag inflator according to claim 1, wherein the inner wall means includes a support means for supporting the fragile portion on at least one surface of the fragile portion. 4. The multi-stage airbag inflator according to claim 3, wherein the supporting means includes at least one hole for allowing gas to flow between the plurality of chambers. 5. The supporting means has a perforated structure having holes for allowing gas to flow between the plurality of chambers, and the weakened portion is the other of the weakened portions on the side remote from the supporting means. 4. The multi-stage airbag according to claim 3, further comprising at least one groove formed in the surface of the groove, the groove forming a rupture line that ruptures the weakened portion in response to gas pressure generated in the one chamber. Inflator. 6. The support means engages the one surface of the fragile portion to prevent the fragile portion from rupturing in response to gas pressure occurring in other chambers of the plurality of chambers. The multistage airbag inflator according to claim 5, which supports. 7. The one surface of the fragile portion is flat and the groove forms a thin walled portion to prevent rupture of the fragile portion in response to gas pressure generated adjacent the one surface. The multi-stage airbag inflator according to claim 6, which facilitates. 8. The inner wall means comprises a heat insulating means for preventing the gas generating means of one of the chambers from being activated by heat generated when the gas generating means of the other chamber is activated. The multi-stage airbag inflator according to claim 1. 9. The inner wall means comprises a structural support having a hole for allowing gas to flow between the plurality of chambers, and the thermal insulation means is supported adjacent to at least one surface of the support. The multi-stage airbag inflator according to claim 8. 10. The multi-stage airbag inflator according to claim 9, wherein the fragile portion of the inner wall means is supported on the other surface of the support on the side away from the heat insulating means.